Soundbar

ABSTRACT

A soundbar with a housing and a plurality of acoustic radiators carried by the housing and configured to output sound for at least left, right, and center audio channels, wherein at least one of the acoustic radiators comprises a dipole acoustic radiator that is configured to emit sound in opposite directions along a main radiation axis.

BACKGROUND

This disclosure relates to a soundbar.

Surround sound audio systems can be configured to reproduce left, right,center, surround, and height channels. Soundbars can be used for theleft, right, and center channels, but are typically not useful for theheight channels.

SUMMARY

All examples and features mentioned below can be combined in anytechnically possible way.

In one aspect a soundbar includes a housing and a plurality of acousticradiators carried by the housing and configured to output sound for atleast left, right, and center audio channels, wherein at least one ofthe acoustic radiators comprises a dipole acoustic radiator that isconfigured to emit sound in opposite directions along a main radiationaxis.

Some examples include one of the above and/or below features, or anycombination thereof. In an example the dipole acoustic radiator isconfigured to output sound for a height audio channel. In an example thesoundbar includes two separate dipole acoustic radiators, wherein one ofthe dipole acoustic radiators is configured to output sound for a leftheight audio channel and the other dipole acoustic radiator isconfigured to output sound for a right height audio channel. In anexample the dipole acoustic radiator is configured to output sound foreither the left or right audio channel. In an example the soundbarincludes two separate dipole acoustic radiators, wherein one of thedipole acoustic radiators is configured to output sound for the leftaudio channel and the other dipole acoustic radiator is configured tooutput sound for the right audio channel.

Some examples include one of the above and/or below features, or anycombination thereof. In some examples the dipole acoustic radiatorcomprises an audio driver mounted in an enclosure such that a frontsurface of the driver is configured to radiate front sound away from theenclosure and an opposing rear surface of the driver is configured toradiate rear sound into the enclosure, and the enclosure defines one ormore openings that are configured to allow the rear sound to escape fromthe enclosure into an external environment. In an example the openingsare configured to allow the rear sound to escape from the enclosurealong the majority of a circumference of the enclosure. In an examplethe openings comprise elongated slots. In an example the housing definestwo opposed ends and a front and rear side, and the dipole acousticradiator is located at one end of the housing such that the enclosure islocated at the one end and the front and rear sides adjacent to the oneend, and the enclosure openings are at the one end and the front andrear sides adjacent to the one end. In an example the soundbar includestwo separate dipole acoustic radiators, one located at each end of thehousing such that their enclosures are located at the ends and the frontand rear sides adjacent to the respective ends, and the enclosureopenings are at the respective ends and the front and rear sidesadjacent to the respective ends. In an example the housing defines aheight between bottom and top sides and the openings comprise elongatedslots that extend along a majority of the height of the housing. In anexample the openings encompass at least 20% of the area of theenclosure.

Some examples include one of the above and/or below features, or anycombination thereof. In some examples the dipole acoustic radiator soundemission defines main lobes forward and backward along the mainradiation axis. In an example the dipole acoustic radiator soundemission further defines nulls along axes that are transverse to themain radiation axis. In an example the nulls exhibit a sound pressurelevel that is at least 10 dB less than the sound pressure level of themain lobes at one or more sound frequencies. In an example the dipoleacoustic radiator is configured to radiate sound in a frequency range of500 Hz and above.

In another aspect a soundbar includes a housing and a plurality ofacoustic radiators carried by the housing and configured to output soundfor at least left, right, center, left height, and right height audiochannels, wherein the plurality of acoustic radiators comprise twoseparate dipole acoustic radiators that are configured to emit sound inopposite directions along a main radiation axis, wherein one of thedipole acoustic radiators is configured to output sound for the leftheight audio channel and the other dipole acoustic radiator isconfigured to output sound for the right height audio channel. Thedipole acoustic radiators define sound emission main lobes forward andrearward along their main radiation axes and further define nullstransverse to their main radiation axes, wherein the nulls exhibit asound pressure level that is at least 10 dB less than the sound pressurelevel of the main lobes at one or more sound frequencies.

Some examples include one of the above and/or below features, or anycombination thereof. In an example the dipole acoustic radiators eachcomprise an audio driver mounted in an enclosure such that a frontsurface of the driver is configured to radiate front sound away from theenclosure and an opposing rear surface of the driver is configured toradiate rear sound into the enclosure, and the enclosure defines one ormore openings that are configured to allow the rear sound to escape fromthe enclosure into an external environment along the majority of acircumference of the enclosure. In an example the housing defines twoopposed ends and a front and rear side, and one of the two separatedipole acoustic radiators is located at each end of the housing suchthat their enclosures are located at the ends and the front and rearsides adjacent to the respective ends, and the enclosure openings are atthe respective ends and the front and rear sides adjacent to therespective ends. In an example the openings of each enclosure encompassat least 20% of the area of the enclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is schematic illustration of a soundbar.

FIG. 2 is a functional block diagram of a surround sound system.

FIG. 3 is a schematic illustration of a dipole acoustic radiator.

FIG. 4 is a schematic illustration of a dipole acoustic radiator thatincludes an enclosure.

FIG. 5 is a perspective view of an end of a housing for a soundbar thatincludes a height-channel transducer.

FIG. 6 is a polar plot of the output of a dipole acoustic radiator for asoundbar.

FIG. 7 is a plot of the sound pressure level at two angular positionsrelative to a dipole acoustic radiator for a soundbar.

FIG. 8 is a plot of the sound pressure level at two angular positionsrelative to a dipole acoustic radiator for a soundbar.

DETAILED DESCRIPTION

Soundbars are used to reproduce at least left, right, and centerchannels of surround sound audio. Surround sound quality is improved ifthe listener can perceive height differences in the sound. Heightchannels are usually reproduced with speakers mounted in the ceiling.Surround sound systems can be simplified if height channels can bereproduced by the soundbar.

In order to perceive height differences in sound produced by a soundbar,the sound needs to be reflected off of the ceiling. Soundbarloudspeakers can be pointed up in order to bounce sound off the ceiling.However, since loudspeakers are generally omni-directional, the soundwill also directly reach the listener, which reduces the height effect.

The present soundbar includes one or more dipole acoustic radiators.Dipole acoustic radiators develop greater sound pressure along theirprimary axis than they do in orthogonal directions. In a polar plot ofsound pressure or sound energy taken radially around a dipole acousticradiator, the highest sound pressure is in two main lobes that extend inopposite directions along the primary axis, while the sound pressure islower in side lobes that extend in opposite directions along an axisthat is orthogonal to the primary axis, sometimes called “nulls.” Insome examples one or both nulls of a dipole acoustic radiator exhibit asound pressure level that is at least 10 dB less than the sound pressurelevel of one or both main lobes, at least at one or more frequencies ofthe radiated sound.

When a dipole acoustic radiator is used to reproduce a height channel ina soundbar, the primary axis can be pointed up, at the ceiling. Thisplacement directs a null to the front of the soundbar, toward thelistener. Accordingly, substantially more sound pressure will reflectoff the ceiling than will directly reach the listener. A result is thatthe height channel is reproduced with less impact from the height sounddirectly reaching the listener, thus increasing the height effect.

In some examples a dipole acoustic radiator can also or alternatively beused to reproduce the left and/or right channel, with a null pointed atthe listening location and a main lobe pointed to the left or rightwhere it can reflect off a side wall of the room in which the soundbaris located. As with the height channel, this left/right channel use ofthe dipole acoustic radiator will reduce the amount of left or rightsound that directly reaches the listener as compared to the reflectedsound that comes from the left or right. A result is that the leftand/or right channel is reproduced with less impact from the left orright sound directly reaching the listener, thus increasing theleft/right separation effect.

A dipole acoustic radiator can be accomplished in multiple manners. Inan example the dipole acoustic radiator includes an acoustic radiatorwith its front and rear substantially open to the environment, so thatthe sound pressure level (SPL) is approximately the same along theprimary axes of the front and rear sides of the diaphragm of theacoustic radiator, at least at some frequencies, while SPL is lower onthe null axes. The extent to which the front and rear are open isrelative. Effective openings for dipole-like operation involve theopenings (and any other aspects of the dipole acoustic radiator thatcontribute to the front and rear-side SPL such as the design of theacoustic cavity) being such that the SPL of the acoustic radiation isgreater along the primary axes than it is along transverse axes,including but not limited to the orthogonal axes. The SPL being the samein both directions along the primary axes is also relative. A truetheoretical dipole acoustic radiator will have a figure eight-shaped SPLpolar plot, with equal primary lobes forward and backward along theprimary axes, and zero SPL nulls at +90 and −90 degrees from the forwarddirection (i.e., along axes that are orthogonal to the primary axes).

In the present soundbar, a dipole acoustic radiator will have higher SPLalong the primary axes than it does along the transverse or orthogonalaxes. In most but not all cases the SPL along the primary axes is atleast 10 dB greater than is the SPL along or close to the orthogonalaxes at some, most, or all of the radiated frequencies. This arrangementprovides sufficient SPL directed upward (for a height channel) or to theleft or right (for a left or right channel) to accomplish a height,left, or right channel where the listener perceives that sound comesfrom above, the left, or the right, respectively, while minimizing theamount of sound projected directly toward the listener located in frontof the soundbar, which would have a negative impact on the perception ofheight or direction.

In another example of a dipole acoustic radiator, two acoustic radiatorscan be mounted back-to-back such that they radiate in oppositedirections. The radiators can be controlled so that they radiatesynchronously. Other designs for dipole acoustic radiators are known inthe technical field and included within the scope of the presentdisclosure.

FIG. 1 is schematic illustration of a soundbar 10. Soundbar 10 includeshousing 12 with top 14, bottom 16, left end 18, and right end 20.Soundbars can have any number of acoustic radiators, but are generallyconfigured to reproduce at least the left, center, and right acousticchannels, as is well known in the field. Present soundbar 10 is alsoconfigured to reproduce left and right height audio channels. Althoughany particular channel may be reproduced by more than one transducer incombination, the acoustic radiators of soundbar 10 are representedfunctionally, with a numbered block representing the one or moreradiators that are used to reproduce any particular channel. Theradiators include those that reproduce a left height channel 28 (andprimarily radiate upwardly, as indicated by arrow 29), those thatreproduce a right height channel 30 (and primarily radiate upwardly, asindicated by arrow 31), those that reproduce a left channel 24 (andprimarily radiate to the left, as indicated by arrow 25), those thatreproduce a right channel 26 (and primarily radiate to the right, asindicated by arrow 27), and those that reproduce a center channel 22(and primarily radiate in a forward direction, as indicated by arrow23). In some examples one or more of the left, right, and centerchannels are reproduced with an array of multiple radiating elementswith controllable delay between elements so that a tight polar patternaimed in a desired direction can be produced. In some examples any oneor more of the left height, right height, left, and right channels maybe reproduced using a dipole acoustic radiator.

FIG. 2 is a functional block diagram of a surround sound system 40,illustrating one non-limiting use of a soundbar. It should be noted thatmany surround sound systems will not have all of the channels noted inthe drawing. Processor 42 is configured to receive input audio signals(over wires, or wirelessly) from audio source 44. Processor 42 providesaudio data or audio signals to the audio transducers of soundbar 46 andany additional transducers that are not included in the soundbar.Soundbar 46 includes transducers that are used to reproduce one or moreof center, left, right, left front height, and right front heightchannels 50, 52, 54, 55, and 56, respectively. Other channels caninclude zero or more of sub-woofer 66, left and right surround 58 and60, respectively, and left and right rear height 62 and 64,respectively. In some examples, such as illustrated in FIG. 1, theheight channel is not broken into front and rear, but rather each side(left height and right height) is handled using a single channel. Notealso that surround sound systems can have additional or differentchannels, and/or additional or different transducers.

FIG. 3 is a schematic illustration of a dipole acoustic radiator 80 thatcomprises audio transducer 82 with radiating surface (e.g., diaphragm)84. Transducer 82 is mounted to panel or other support 86 such that itis open to the front and rear. As diaphragm 84 is moved up and down itproduces sound pressure that moves outward, along forward and rearprimary radiation axes 90 and 91 that are, in an ideal sense, parallel.For an ideal radiator the front and rear sound pressure is the same, andis out of phase. Accordingly, the sound along the two axes that areorthogonal to axes 90 and 91 (not shown) cancels, producing nulls atabout 90 degrees to the primary axes. As is known in the field, a polarplot of the dipole acoustic radiator looks like a figure eight alignedalong the primary axes. In some examples the dipole acoustic radiator isconfigured such that a primary radiation axis is pointed in a desireddirection or at a desired location and/or a null is pointed in a desireddirection or at a desired location. In an example of a dipole acousticradiator used for a soundbar height channel a primary radiation axis ispointed up toward the ceiling and a null is pointed outward toward theexpected location of a person listening to the sound (e.g., directly infront of the soundbar, which is intended to be mounted below or above atelevision). In this example sound will hit and be reflected from theceiling, and thus be perceived as emanating from above the listener,while the null pointed at the listener will help to maintain the heightperception. In an example of a dipole acoustic radiator used for asoundbar left or right channel a primary radiation axis is pointed tothe left or right, toward a side wall of the room, and a null is pointedoutward toward the expected location of a person listening to the sound(e.g., directly in front of the soundbar, which is intended to bemounted below or above a television). In this example sound will hit andbe reflected from the left or right wall, and thus be perceived asemanating from the left or right of the listener, while the null pointedat the listener will help to maintain the left or right perception. Insome examples dipole acoustic radiator 80 is used as a transducer forthe left height, right height, left, and/or right channels of asoundbar.

FIG. 4 is a schematic illustration of a dipole acoustic radiator 92 thatcan be used in a soundbar. Dipole acoustic radiator 92 includestransducer 95 mounted in enclosure 93. Enclosure 93 includes top 94 withopening 96 for emitting front-side radiation. One or more sides and/orthe bottom of enclosure 93 are open sufficiently such that sound is alsoemitted from the rear of the transducer. The area and location ofopenings from the rear of the transducer to the environment in partdictate how close to ideal the dipole acoustic radiator radiationpattern is, and the frequencies at which dipole behavior is exhibited.The sizes, shapes, and locations of rear openings can be selected toachieve a desired dipole performance given any constraints due to thephysical design of a soundbar in which dipole acoustic radiator 92 islocated.

FIG. 5 is a perspective view of part of the left end 100 of a housingfor a soundbar that includes a height-channel transducer, in thisinstance a left height channel dipole acoustic radiator (not shown). Endenclosure 110 includes oval opening 114 in top 112 that is configured tohold an oval-shaped acoustic transducer (not shown) that is used togenerate the sound for a dipole acoustic radiator. An oval shape isexemplary and not limiting of the scope of this disclosure, as thetransducer's shape could be round, rectangular, or otherwise. In asoundbar in which both left and right height channels are reproducedusing two separate dipole acoustic radiators, the right end of thehousing (not shown) could be identical to the left end, and also carry asingle dipole transducer for the right height channel.

Enclosure 110 is further defined by end wall 118, front wall 116, andrear wall 120. In an example each of these three walls includes one ormore openings that allow sound pressure to escape from the rear of thetransducer into the environment. The openings can be round, oval, or anyshape. In examples herein the openings encompass from 0 to 100% of theareas of the walls. Since the front and rear sides of the transducer areboth open to the environment, the transducer will act as a dipoleacoustic radiator. Bottom wall 104 does not include openings because inmost cases the soundbar will sit on a surface, which would block anysuch openings. However, the bottom could include openings. Any one ormore of the sides and bottom of enclosure 110 can have a desired openarea, with such open area accomplished with an entirely open side, orone or more openings of any desired size, shape and location. In anexample the openings are elongated slots that extend along most of theheight of each of the three sides. In an example the openings extendalong a majority of the circumference of the enclosure. In some examplesthe openings encompass at least about 20% of the area of the enclosurebehind the transducer diaphragm, to accomplish a dipole behavior that issufficient to reproduce a height channel.

Also shown are a small portion 102 of the rest of the soundbar housing,including part of opening 130 that is configured to house the leftchannel transducer(s) (not shown). Not shown are locations for othertransducers of the soundbar, such as the transducer(s) for the centerand right channels, and a right height channel. In some examples asoundbar includes a left height channel and a right height channel. Inan example one dipole acoustic radiator is used to reproduce the rightheight channel and a separate dipole acoustic radiator is used toreproduce the left height channel.

FIG. 6 is a polar plot 150 of the output of a dipole acoustic radiatorfor a soundbar. Plot 150 includes the SPL (in dB) at 360 degrees aroundthe transducer. The zero degree direction is on-axis of the front sideradiation while the 180 degree direction is on-axis of the rear sideradiation. The radiation at 90 and 270 degrees are on axes that areorthogonal to the front and rear side primary axes, termed the nullaxes. As can be seen, at 250 and 501 Hz the plot is essentially a puredipole, with essentially equal SPL at zero and 180 degrees and about 13dB or more lower SPL at 90 and 270 degrees. At 1000 Hz it starts totransition and the side nulls soften to about 8 dB. Above that frequencythe radiator becomes more unipolar (up firing) but side energy isnaturally low so the objectives of the dipole radiator (greater SPLpointed up at the ceiling than directly toward the listener) are stillmet. When the front side axis is pointed up, at the ceiling, and a nullis pointed directly in front of the soundbar, a listener located infront of the soundbar will perceive the sound as emanating from theceiling. The dipole acoustic radiator is thus able to reproduce a heightchannel.

FIG. 7 is a plot of the sound pressure level across a large frequencyrange (100 Hz to about 20 kHz) at two angular positions relative to adipole acoustic radiator that can be used in a soundbar similar to thatshown in FIG. 5. Plot line 172 is along the front primary axis (i.e., atzero degrees on a polar plot) and plot line 174 is at 90 degrees. Thepeaks just above 1000 Hz are due to Helmholtz resonance caused by theinternal volume of the rear side enclosure combined with the area of theopenings to the environment. As can be seen, the null axis radiation isless than that along the primary axis across the entire spectrum, and atmany frequencies the difference is 5 dB or more. FIG. 8 is a similarplot of the sound pressure level at 20 degrees (line 182) and 90 degrees(line 184) for the same transducer design. The separation is evengreater at these angular positions. In some examples for the design of aleft or right height channel, understanding SPL at 20 and 90 degrees canbe useful to understanding the sound that is likely to reflect off theceiling and reach the listener (the 20 degree sound) and the sound thatis likely to directly reach the listener (the 90 degree sound). Theplots of FIGS. 7 and 8 support the dipole-like output of two angularpositions separated by 70-90 degrees relative to a dipole acousticradiator for a soundbar across the entire illustrated frequency range.

In some examples the dipole is oriented so as to maintain the greatestdifference between the energy directed upward toward the ceiling and theenergy directed toward the listener. In such examples, the directivitycurve of the dipole has an upwards and downwards beam and a null that isthree dimensional in the horizontal plane. The null dip is quite narrowand deep, while the upward lobe is broad and more gradually changingwith angle. If the dipole were angled slightly forward rather than beingdirected straight up, the energy reflected off the ceiling could beslightly greater (about 1 dB), but the deepest null would not bedirected toward the user (in the horizontal plane), thereby reducing thebenefit of the dipole configuration. As the slope around the null ismuch greater than the slope of the upward lobe, the greatest differencebetween the two angles is achieved if the null is in the horizontalplane. Thus, the greatest difference is generally achieved when theprimary axis is pointed directly up rather than angled at say 20 degreesfrom the vertical. However, in some implementations, the dipoledriver(s) could be angled, such as angled 1-30 degrees toward or awayfrom the user, such as 20 degrees toward the user, and even for thoseangled implementations, the dipole configuration can help improve thedirectionality of the audio output. The dipole primary axis could alsobe angled slightly to the left or right (e.g., angling the dipole drivertoward or away from the center of the soundbar). Outwardly directeddipoles could, e.g., spread the apparent widths of the two heightchannels. For such configurations, the dipole driver(s) could be angled1-30 degrees inward or outward, such as 20 degrees outward, depending onthe desired configuration.

The dipole driver(s) are beneficial when used to render audio that isintended to be spatialized. For example, use of one or more dipoledrivers can improve output of audio that includes a height component,such as Dolby Atmos® audio content or other object-oriented audiocontent, as use of one or more dipole drivers can improve audio outputdirectivity and thus provide a better sense of audio height and/ordiffuseness.

In the far-field in particular, the dipole behavior can lead to lowfrequency cancelation and thus an extra about 6 dB per octave roll-offthat should be equalized out. So there is a practical limit to how lowin frequency to drive the dipole transducer based on the size of thedriver and its excursion capability. 500 Hz is an approximate practicallower limit for the dipole acoustic radiator, in part because theperception of height is reduced at lower frequencies so there is lessbenefit to going below about 500 Hz. In some examples the dipoleacoustic radiator is configured to reproduce sound in a frequency wheredipole radiation causes a 10-15 dB loss in low-frequency output, ideallyfrom the highest frequencies down to around 500 Hz, or below.

SPL measurements of a dipole acoustic radiator can assist with soundbardesign and the placement and orientation of the driver(s) and the designconsiderations (e.g., the rear enclosure volume and rear opening area)of the driver's enclosure. SPL measurements and polar plots areinformation that can be used to achieve a good soundbar and surroundsound design compromise. SPL measurements provide information about thefrequency response. Also, SPL measurements can be used to determinewhether the design accomplishes good spacing between the curves (10 to15 dB), uniformity of spacing across the frequency range, and anadequate frequency response (relatively smooth and not so rolled off atlow frequencies that an excessive boost might be needed).

Elements of figures are shown and described as discrete elements in ablock diagram. These may be implemented as one or more of analogcircuitry or digital circuitry. Alternatively, or additionally, they maybe implemented with one or more microprocessors executing softwareinstructions. The software instructions can include digital signalprocessing instructions. Operations may be performed by analog circuitryor by a microprocessor executing software that performs the equivalentof the analog operation. Signal lines may be implemented as discreteanalog or digital signal lines, as a discrete digital signal line withappropriate signal processing that is able to process separate signals,and/or as elements of a wireless communication system.

When processes are represented or implied in the block diagram, thesteps may be performed by one element or a plurality of elements. Thesteps may be performed together or at different times. The elements thatperform the activities may be physically the same or proximate oneanother, or may be physically separate. One element may perform theactions of more than one block. Audio signals may be encoded or not, andmay be transmitted in either digital or analog form. Conventional audiosignal processing equipment and operations are in some cases omittedfrom the drawing.

A number of implementations have been described. Nevertheless, it willbe understood that additional modifications may be made withoutdeparting from the scope of the inventive concepts described herein,and, accordingly, other examples are within the scope of the followingclaims.

1. A soundbar that is configured to be located in a listening area thathas a ceiling located above the soundbar, wherein the soundbar isconfigured to produce sound that is provided to an expected location ofa person in the listening area, the soundbar comprising: a housing; anda plurality of acoustic radiators carried by the housing and configuredto output sound for at least a left audio channel, a right audiochannel, a height audio channel, and a center audio channel, wherein atleast one of the acoustic radiators comprises a dipole acoustic radiatorthat is configured to emit sound for the height audio channel inopposite directions along a main radiation axis that is directed upwardtoward the ceiling, and wherein the dipole acoustic radiator defines anull axis that is orthogonal to the main radiation axis and is directedtoward the expected location of the person in the listening area;wherein a sound pressure level along the main radiation axis is greaterthan the sound pressure level along the null axis, so that the heightchannel is reproduced by more sound pressure radiated along the mainradiation axis and reflecting off the ceiling and reaching the expectedlocation of the person as compared to sound radiated along the null axisthat directly reaches the expected location of the person.
 2. (canceled)3. The soundbar of claim 1 comprising two separate dipole acousticradiators, wherein a left height dipole acoustic radiators is configuredto output sound for a left height audio channel and a right heightdipole acoustic radiator is configured to output sound for a rightheight audio channel, wherein the left height and right height dipoleacoustic radiators are each configured to emit sound in oppositedirections along a main radiation axis that is directed upward towardthe ceiling, and wherein each dipole acoustic radiator defines a nullaxis that is orthogonal to the main radiation axis and is directedtoward the expected location of the person in the listening area;wherein a sound pressure level along the main radiation axis is greaterthan the sound pressure level along the null axis, so that the heightchannel is reproduced by more sound pressure radiated along the mainradiation axis and reflecting off the ceiling and reaching the expectedlocation of the person as compared to sound radiated along the null axisthat directly reaches the expected location of the person.
 4. Thesoundbar of claim 1 further comprising a dipole acoustic radiator thatis configured to output sound for either the left or right audiochannel.
 5. The soundbar of claim 1 wherein the listening area has leftand right walls, the soundbar further comprising separate left and rightdipole acoustic radiators that are configured to reproduce left andright audio channels, respectively, wherein the left dipole acousticradiators is configured to output sound for the left audio channel andthe right dipole acoustic radiator is configured to output sound for theright audio channel, wherein the left and right dipole acousticradiators are each configured to emit sound in opposite directions alonga main radiation axis that is directed outward at an angle toward one ofthe left and right walls, and wherein the left and right dipole acousticradiators each define a null axis that is orthogonal to the mainradiation axis and is directed toward the expected location of theperson in the listening area; wherein a sound pressure level along themain radiation axis is greater than the sound pressure level along thenull axis, so that the channel is reproduced by more sound pressureradiated along the main radiation axis and reflecting off the left orright wall and reaching the expected location of the person as comparedto sound radiated along the null axis that directly reaches the expectedlocation of the person.
 6. The soundbar of claim 1 wherein the dipoleacoustic radiator comprises an audio driver mounted in an enclosure suchthat a front surface of the driver is configured to radiate front soundaway from the enclosure and an opposing rear surface of the driver isconfigured to radiate rear sound into the enclosure, and wherein theenclosure defines one or more openings that are configured to allow therear sound to escape from the enclosure into an external environment. 7.The soundbar of claim 6 wherein the openings are configured to allow therear sound to escape from the enclosure along the majority of acircumference of the enclosure.
 8. The soundbar of claim 6 wherein theopenings comprise elongated slots.
 9. The soundbar of claim 6 whereinthe housing defines two opposed ends and a front and rear side, andwherein the dipole acoustic radiator for the height audio channel islocated at one end of the housing such that the enclosure in which theaudio driver is mounted is located at the one end and the front and rearsides adjacent to the one end, and wherein the enclosure openings are atthe one end and the front and rear sides adjacent to the one end. 10.The soundbar of claim 9 comprising two separate left and right heightdipole acoustic radiators, one located at each end of the housing suchthat their enclosures are located at the ends and the front and rearsides adjacent to the respective ends, and wherein the enclosureopenings are at the respective ends and the front and rear sidesadjacent to the respective ends.
 11. The soundbar of claim 9 wherein thehousing defines a height between bottom and top sides and the openingscomprise elongated slots that extend along a majority of the height ofthe housing.
 12. The soundbar of claim 6 wherein the openings encompassat least 20% of the area of the enclosure.
 13. The soundbar of claim 1wherein the dipole acoustic radiator sound emission defines main lobesforward and backward along the main radiation axis.
 14. The soundbar ofclaim 13 wherein the dipole acoustic radiator sound emission furtherdefines a nulls along the null axis.
 15. The soundbar of claim 14wherein the nulls exhibits a sound pressure level that is at least 10 dBless than the sound pressure level of the main lobes at one or moresound frequencies.
 16. The soundbar of claim 1 wherein the dipoleacoustic radiator is configured to radiate sound in a frequency range of500 Hz and above.
 17. A soundbar that is configured to be located in alistening area that has a ceiling located above the soundbar, whereinthe soundbar is configured to produce sound that is provided to anexpected location of a person in the listening area, the soundbarcomprising: a housing; and a plurality of acoustic radiators carried bythe housing and configured to output sound for at least left, right,center, left height, and right height audio channels, wherein theplurality of acoustic radiators comprise two separate dipole acousticradiators that are configured to emit sound in opposite directions alonga main radiation axis, wherein one of the dipole acoustic radiators isconfigured to output sound for the left height audio channel and theother dipole acoustic radiator is configured to output sound for theright height audio channel; wherein the dipole acoustic radiators definesound emission main lobes forward and backward along their mainradiation axes and further define nulls transverse to their mainradiation axes, wherein the nulls exhibit a sound pressure level that isat least 10 dB less than the sound pressure level of the main lobes atone or more sound frequencies; wherein the left height and right heightdipole acoustic radiators are each configured to such that their mainradiation axis is directed upward toward the ceiling, and wherein thenulls of each dipole acoustic radiator are orthogonal to the mainradiation axis and are directed toward the expected location of theperson in the listening area; wherein the height channels are reproducedby more sound pressure radiated along the main radiation axis andreflecting off the ceiling and reaching the expected location of theperson as compared to sound radiated along the null axis that directlyreaches the expected location of the person.
 18. The soundbar of claim17 wherein the dipole acoustic radiators each comprise an audio drivermounted in an enclosure such that a front surface of the driver isconfigured to radiate front sound away from the enclosure and anopposing rear surface of the driver is configured to radiate rear soundinto the enclosure, and wherein the enclosure defines one or moreopenings that are configured to allow the rear sound to escape from theenclosure into an external environment along the majority of acircumference of the enclosure.
 19. The soundbar of claim 18 wherein thehousing defines two opposed ends and a front and rear side, and whereinone of the two separate dipole acoustic radiators is located at each endof the housing such that their enclosures are located at the ends andthe front and rear sides adjacent to the respective ends, and whereinthe enclosure openings are at the respective ends and the front and rearsides adjacent to the respective ends.
 20. The soundbar of claim 19wherein the openings of each enclosure encompass at least 20% of thearea of the enclosure.
 21. The soundbar of claim 1 wherein the mainradiation axis of the height audio channel is at an angle relative tothe ceiling of between 90 degrees, and 60 degrees toward the expectedlocation of the person in the listening area.